Passive immunity

resistance to an infectious agent as a result of a transfer of antibodies from a previously immunized animal to an unprotected animal. The transfer of antibodies from a cow to a calf by the colostrum is an example of passive immunity.

Pasteurization

microbiocidal heat treatment aimed at reducing the number of any pathogenic microorganisms in milk and liquid milk products, if present, to a level at which they do not constitute a significant health hazard. Pasteurization conditions are designed to effectively destroy the organisms Mycobacterium tuberculosis and Coxiella burnettii. (Codex Alimentarius)

Potassium dichromate

Predicted Difference (PD)

Estimate of the genetic transmitting ability of dairy bulls for performance traits. Pd is defined as the amount by which daughters of a bull will, on the average, differ in performance from the average breed performance in the genetic base period.